Process for producing large-size formed articles consisting of a modified polyamide

A process for producing molded articles consisting of a polyamide, comprising casting or rotationally molding a plymerizable mixture comprising an omega-lactam corresponding to the polyamide and:

• a) a polymerization catalyst selected from the group consisting of sodium and potassium salts of said omega-lactam and mixtures thereof containing a functional group M, where M is an alkali ion;
• b) a polyoxyalkylene polyamine having NH.sub.2 terminations, as an elastomerizing agent, having a molecular weight from 400 to 5,000 and an aminic functionality substantially ranging from 1.9 to 2.5;
• and
• c) an activator consisting of a polyiocyanate having all the isocyanic (NCO) groups blocked with a lactam;
• wherein the reagents are distributed, prior to polymerizatio, among two distinct feeding tanks such that a part of the omega-lactam, catalyst (a) and polyoxyalkylene polyamine (b) are fed to one of said tanks, the remaining amount of omega-lactam together with activator (c) are fed to the other of said tanks, and then the contents of the respective tanks are combined to form a mixture and said mixture is fed at a temperature from 105.degree. to 125.degree. C. to a mold which is heated to a temperature from 130.degree. to 170.degree. C.